Over the past five years, research and development for clinical diagnostic systems based on lab-on-a-chip technologies have increased tremendously. Such systems hold great promise for clinical diagnostics. They consume sample material and reagents only in extremely low volumes. Individual small chips can be inexpensive and disposable. Time from sampling to result tends to be very short. The most advanced chip designs can perform all analytical functions—sampling, sample pretreatment; separation, dilution, and mixing steps; chemical reactions; and detection—in a single integrated microfluidic circuit. Lab-on-a-chip systems allow designers to create small, portable, rugged, low-cost, and easy-to-use diagnostic instruments that offer high levels of capability and versatility. Microfluidics—fluids flowing in microchannel makes possible the design of analytical devices and assay formats that would not function on a larger scale.
Lab-on-a-chip technologies attempt to emulate the laboratory procedures that would be performed on a sample within a Microfabricated structure. The most successful devices have been those that operate on fluid samples. A large number of chemical processing, purification, and reaction procedures have been demonstrated on these devices. Some degree of monolithic integration of chemical processes has been demonstrated to produce devices that perform a complete chemical measurement procedure. These devices are based upon accepted laboratory procedures of analysis and thus are able to accommodate more complex sample matrices than conventional chemical sensing.
Recent advances in molecular and cell biology have been produced in great part as a result of the development of rapid and efficient analytical techniques. Due to miniaturization and multiplexing, techniques like gene chip or biochip enable the characterization of complete genomes in a single experimental setup. PCR (Polymerase chain reaction) is a molecular biology method for the in-vivo amplification of nuclear acid molecules. The PCR technique is rapidly replacing other time consuming and less sensitive techniques for identification of biological species and pathogens in forensic, environmental, clinical and industrial samples. Among the biotechniques, PCR has become the most important analytical step in life sciences laboratories for a large number of molecular and clinical diagnostics. Important developments made in PCR technology like real-time PCR, have led to rapid reaction processes compared to conventional methods. During the past several years, microfabrication technology has been expanded to the miniaturization of the reaction and analysis system such as PCR analysis with the intention of further reducing analysis time and consumption of reagents.
In most PCR's available now, instantaneous temperature changes are not possible because of sample, container, and cycler heat capacities, and extended amplification times of 2 to 6 hours result. During the periods when sample temperature is making a transition from one temperature to another, extraneous, undesirable reactions occur that consume important reagents and create unwanted interfering compounds.
LTCC is used in packaging semiconductor devices. This system enables integration of electrical and structural function. The layer by layer fabrication sequence in LTCC fabrication process enables creation of three dimensional structures with integrated electrical elements with ease. In addition, it is cheaper to process when compared to silicon processing. A chip is fabricated on a ceramic substrate like LTCC (Low Temperature Co-fired Ceramic) enables integration of mechanical and electrical elements easily and cheaply.
Use of a portable computing platform like PDA gives the system enough computing power to control the electronics and provide a rich yet simple user interface to display the data. It also makes the entire system modular and hence enables easy upgradation the system with minimal cost to the user.